A business is proposed for providing a predetermined service to a user having a plurality of terminal devices such as personal computers, tablet terminal devices, or mobile terminal devices coupled to the internet via a service server that provides services to terminal devices.
In order for a single user to receive a service from a service server with the use of a plurality of terminal devices, performing authentication processing using the same ID and the same password (referred to as “ID/PW” hereinafter) for the respective terminal devices is burdensome. Thus, a single sign-on technique is known in the related art (for example, see Patent Document 1). According to the single sign-on technique, when a logon operation is once performed by any of a plurality of terminal devices, a service can be used in the plurality of terminal devices.
There may be a case in which one terminal device of a plurality of terminal devices request an authentication server to change a plurality of services simultaneously, and after the requested processing is normally completed, another terminal device of the plurality of terminal devices is coupled to a service server by an ID/PW that is the same as that of the one terminal device in order to use new services. In this case, the authentication server determines a service with respect to the terminal device that inputs the ID/PW by an individual ID to the service server. At that time, there is a method (method 1) in which the authentication server and service servers always coordinate, and when the another terminal device is coupled to an intended service server, the service server performs substitute authentication for the authentication server to continuously provide a service. Further, there is a method (method 2) in which the another terminal device is necessarily coupled to the authentication server, and after being authenticated, the another terminal device is coupled to respective service servers in accordance with information for respective services managed by the authentication server.
However, in the single sign-on technique, one ID/PW is transmitted from one terminal device to another terminal device, and the another terminal device waits for the ID/PW transmitted from the one terminal device while being coupled to the internet. Thus, even when the one terminal device is authenticated by the ID/PW and a module for using a new service is registered, there is no means for transmitting the module for using the new service to the another terminal device because the another terminal device is not coupled to the service server that provides the new service. Hence, it is difficult for the another terminal device to obtain the module for using the new service and to use the new service.
Further, in the method 1, service servers have to understand services with respect to IDs held by the authentication server. Therefore, the authentication server frequently updates information with respect to each of the service servers, and the communication volume between the authentication server and the service servers is enormous.
Further, in the method 2, the terminal device of the user is necessarily coupled to the authentication server, and after being authenticated, the terminal device is coupled to service servers in accordance with services for respective IDs managed by the authentication server. Accordingly, all terminal devices use services via the authentication server, the terminal devices and the authentication server are very frequently accessed, and a processing load of a CPU of the authentication server is high.